Toilet apparatus

ABSTRACT

An embodiment provides a toilet having a toilet pan  11 , an outlet pipe  78  for the contents of the pan, a closeable lid  21  on the pan forming with the pan a waste receptacle chamber, a seal  22  between the lid  21  and the pan  11 , means  12  for introducing water into the chamber to wash the internal surface of the pan, and means  2  for subsequently increasing the air pressure in the chamber to force the contents of the pan through the outlet pipe.

This invention relates to toilet apparatus, and in particular to suchapparatus that uses little water in each flushing cycle.

A conventional toilet or water closet disposes of waste matter byhydraulic means alone by relying on a large enough volume of water togenerate sufficient force to expel waste from the toilet pan. Manytoilet systems exist which dispose of waste matter with a negativepneumatic pressure e.g. by drawing waste from the pan through an outletpipe using various valves, pumps, vacuum chambers, transfer tanks andthe like. Such systems do reduce water consumption but are generallydifficult to manufacture, and are inconvenient to install, use andmaintain.

U.S. Pat. No. 4,306,321 discloses a water closet for boats and caravansin which a sealed chamber, which includes the toilet pan, is pressurizedto discharge the contents of the pan through a discharge valve into aholding tank, the chamber being subsequently pressurised again todischarge flushing water through the outlet valve to clean the valve.DE-A-19 623 331 and FR-A-2 696 200 both provide flushing water underpressure to a sealed pan/chamber to flush the contents of the panthrough an outlet pipe, but make no provision for increasing thepressure in the chamber.

It is an object of the present invention to obviate or mitigate thesedifficulties by providing toilet apparatus which uses a positivepressure to discharge waste matter from the pan to an outlet pipe thusreducing water consumption. Such apparatus has the additional advantagethat as the outlet pipe is unobstructed by valves or other equipment thetoilet can also be used in a conventional way.

The present invention is toilet apparatus comprising a toilet pan, anoutlet pipe for the contents of the pan a closeable lid on the panforming with the pan a waste receptacle chamber, a seal between the lidand the pan, means for introducing water into the chamber to wash theinternal surface of the pan, and means for subsequently increasing theair pressure in the chamber to force the contents of the pan through theoutlet pipe.

Preferably, means are provided to pressurise the water introduced towash the internal surface of the pan.

The lid may be provided with a locking mechanism for securing the lid inits closed position.

A locking sensor may be associated with the locking mechanism to detectlocking of the lid and initiate operation of the apparatus.

In a preferred embodiment of the invention, the outlet pipe is formedwith an S-bend water trap.

The means for increasing the air pressure in the chamber may include anair displacement unit connected to the chamber and, preferably also tothe water cistern. The unit may comprise a piston movable in a cylinder.The piston moving in the cylinder in one stroke displaces a volume ofair sufficient to provide the pressure in the chamber required to expelthe contents of the pan. The piston may be double acting, the otherstroke of the piston providing the air to pressurise the cistern andthus the water washing the internal surface of the pan before thecontents of the pan are expelled.

The pan is provided with inlets for the water for washing its surface,these inlets being located at the top of the pan and being connected tothe cistern by means which prevent the escape of air from the chamber.

Preferably, a cistern is connected to the pan by two pipes eachincorporating siphon. One pipe is normally closed but may be openedmanually to actuate the siphon, while the other pipe is open and may actas an overflow outlet. The cistern is provided with an aperturesufficient to relay pneumatic pressure and is connected to the airdisplacement unit. When the air displacement unit is activated, thedisplaced air pressurises the cistern and, all vents and pipes to theexterior being closed, the water in the cistern is forced through theopen siphon and into the pan. By venting the overflow pipe when thewater level falls to a predetermined level, the pressure in the cisterncan be released while allowing continued siphonic flow from the cisternto the pan.

Operation of the air displacement unit may be triggered by the lockingof the lid, the locking action being detected by a sensor.

The toilet apparatus may be fitted with a tipping/holding/siphon tankwhich may be pneumatically actuated/emptied.

An embodiment of the present invention will now be described, by way ofexample, with reference to the accompanying drawings, in which:

FIG. 1 is a partially cut away perspective view of toilet apparatusaccording to the present invention;

FIG. 2 is a perspective view in cross-section of the chamber and airdisplacement unit of FIG. 1; and

FIG. 3 is a partially cut away perspective view of the cistern and panused in FIG. 1.

Referring now to the drawings, FIG. 1 shows the complete toiletapparatus generally indicated at 1. An air displacement unit 2 is showninstalled on runners 3 secured to chassis guides 4 by fasteners (notillustrated) thus enabling the unit 2 to be easily withdrawn andinstalled as required. A power supply 5 enters a control box 6 whichcontains a proximity sensor 7 and control apparatus (not illustrated),and is connected to a second proximity sensor 8 by a cable 9. The cable9 passes into a guide tube 10 which positions the sensor 8 inside thepan 11 of the toilet close to a locking bolt 34 as will be laterdescribed.

A cistern 12 has a lid 13 secured on a seal 14 by bolts passing throughholes 15. An air hose 16 connects the air displacement unit 2 to thecistern 12 through a connector 17, thus enabling the cistern to bepressurised. A float valve inlet 18 is connected to a suitable watersupply, and an overflow/vent pipe is shown at 71.

The pan 11 has a seat 20, a lid 21 and a removable lid seal/lockingassembly 22. The lid 21 is provided with hinge brackets 23 and is raisedand lowered around chassis outriggers 24 (FIG. 2) as will be explainedlater. Hinge brackets 23 have a rebate 25 sufficient to receive theseal/locking assembly lip at guide points 26. The seal/locking assembly22 is further provided with a hook 27 thus enabling it to be slid underthe lid 21 and secured by a peg 28 in holes 29, while simultaneouslyengaging the lip guide points 26 in the hinge bracket rebates 25. Thelip seal 30 is fixed to the locking assembly 22 and makes an air tightseal with the rim 31 of the pan 11 when the lid is closed. A lockingassembly handle 32 actuates the locking mechanism with a pull/pushaction through internal cams (not illustrated) which turn a shaft 33thus relaying the movement to a locking bolt 34 (FIG. 2).

It will be appreciated that with such an arrangement a conventionaltoilet lid can be converted to a sealable, locking lid. The locking bolt34 is provided with a magnetic tip 35 which enables the bolt to activatethe sensor 8 when in the locking position. The locking action of the lidalso initiates a flushing cycle by actuating the air displacement unit2.

FIG. 2 shows the air displacement unit 2 and its connection to the pan11 through connectors 36 and 37 which are a male and female tapered fitand have between them a seal to form an air tight connection. It will beappreciated that, with such an arrangement, as the unit.2 is slid intoposition on the chassis guides 4, the connectors are automaticallyaligned to form an air tight connection capable of relaying air underpressure from the unit 2 to the pan.

The air displacement unit 2 consists of an end plate 39 fastened to acylindrical housing or cylinder 40 in which is located a fixedelectromagnet 41 around a central guide tube 42. A second electromagnet43 is fixed to a piston 44 and has a central guide rod 4S forming an airtight fit in the guide tube 42. The piston is provided with a pneumaticseal 47 and is free to travel along cylinder 40. In FIG. 2, the unit 2is shown in its rest position.

It will be appreciated that when the polarities of the electromagnets 41and 43 are such that they are mutually attracted, the piston 44 is drawnalong the cylinder 40 in the direction of the arrow A, thus displacingair in the cylinder 40 and forcing it through an aperture 48 and throughthe hose 16 into the cistern 12. Once the piston has reached the end ofits travel, the proximity sensor 7 detects this and changes the polarityof one of the electromagnets 41 and 43 so that they now repel eachother. The piston 44 is then driven back along the cylinder 40 in thedirection of the arrow B thus again displacing the air in the cylinder40. This displaced air is forced through connectors 36 and 37 and intothe sealed pan chamber. Once the piston 44 has reached the end of itstravel a proximity sensor 50 detects this and causes the electromagnets41 and 43 to be deenergised. The air displacement unit 2 is reset oncethe sensor 8 senses that the lid 21 has been opened. Air vents 51 are offlap-valve type and allow an inward flow of air to the cylinder 40sufficient to prevent a vacuum developing behind the piston 44. Thepiston 44 may be driven manually by a handle 52 (FIG. 1) which isconnected to the guide rod 45.

The seat hinge brackets 53 and lid hinge brackets 23 are connected tothe chassis outriggers 24 by hinge pins and are free to pivot aroundthem.

FIG. 3 shows the cistern 12. A primary siphon 55 connects to the waterpipe 56 which in turn connects to the pan 11 at the connector 57. Theconnector 57 is provided with a flap valve 58 which allows the flow ofair and water only in the direction of the arrow C. This allows thecistern to discharge into the pan while blocking the escape of air fromthe pan 11. The primary siphon 55 is provided with a flap valve 59 forpreventing the flow of water from the cistern 12. Water flow through thesiphon 55 is achieved by lifting the plunger 60 which is connected to asiphon actuator 61 and a flap-valve lever 62 which is pivoted on afulcrum 63.

It will be appreciated that with such an arrangement the siphon isnormally blocked, but by lifting the plunger 60 the flap valve is openedby lever 62 and siphonic flow is started by the actuator 61 thusdepositing the contents of the cistern into the pan 11 in a sufficientquantity to flush the pan. Conveniently, means to lift the plunger 60 isprovided by the handle 64, connecting rod 65 and lever 66.

A secondary siphon 67 consists of an open tube provided with a bellmouth 68 to facilitate effective breaking of its siphon. The siphon 67connects to a water pipe 69 which enters the pan 11 and distributeswater over the surface of the pan through nozzles 70 located under therim of the pan 11, thus providing an efficient spray pattern for washingthe pan. With such an arrangement an open overflow route to the pan 11is always provided. The nozzles 70 and pipe 69 may be fitted with valvesfor inhibiting the escape of air from the pan 11.

An overflow pipe 71 connects to the cistern 12 and is provided with anadditional aperture around its circumference 72. A sleeve is connectedto a float 75 by a rod 76 and fits over the overflow pipe 71 where it isfree to swivel upon it. Two apertures 74 are provided such that assleeve 73 turns aperture 72 may be exposed or obscured by sleeveapertures 74. An end cap 77 is an air tight fit over pipe 71 and retainsthe sleeve 73 in place. Thus, as the water level in the cistern changesthe float 75 rises and falls accordingly thus turning the sleeve 73 onthe pipe 71 which opens and closes cistern vent through apertures 72 and74.

It will be appreciated that with such an arrangement waste is depositedinto the pan 11 and the lid is closed and locked. The locking action ofthe lid 22 triggers the sensor 8 to activate the air displacement unit 2causing the piston to be driven forward to force air into cisternthrough the hose 16. As the cistern water level is high, the pipeaperture 72 is obscured and there is no vent for displaced air.Consequently, water is forced through the open secondary siphon 67 andinto the pan 11 where the nozzles 70 provide a spray pattern to wash thesurface of the pan. As the cistern water level drops, the float 75 dropsthus exposing the aperture 72 whereupon pressurised air is vented viaaperture 74. Air resistance to the piston 44 drops and the pistonquickly reaches the end of its travel. Water is still able to flowthrough the open siphon at a reduced rate due to gravity.

The direction of piston 44 is now reversed and the air inside the sealedpan chamber is pressurised, whereupon waste is forced through the outletpipe 78. The piston 44 reaches the end of its travel and the flushingcycle ends. However the siphon 67 is still active and a quantity ofwater sufficient to replenish the water trap seal 78 is deposited intothe pan 11 before the water level drops to the level of the bell mouth68 and the siphon is broken. The cistern water level is then replenishedvia the float valve and the float 75 rises thus closing the vent 72.

In the event of inlet valve failure, the float 75 rises thus aligningthe pipe aperture 72 with the second aperture 74 of the sleeve, allowingwater to drain away. Alternatively, rising water may drain away throughthe open siphon to the pan 11. Other embodiments of the invention mayprovide an overflow via the cistern hose 16 and air displacementequipment.

It will be apparent that the toilet apparatus may be used in aconventional manual hydraulic flush mode by using the handle 64.

While the air displacement unit as described is operated electrically ormanually, it could be modified to operate mechanically, hydraulically orpneumatically.

In a further modification of the embodiment described, the cistern isnot pressurised, and the piston may be either single acting, in whichcase the return stroke serves merely to reset the unit, or double actingin which case the return stroke serves to pressurise the chamber in asecond flushing cycle.

The air displacement unit may take other forms including a diaphragm anair pump or a reservoir of compressed air.

In a further modification of the embodiment, the air displacement unittakes the form of a compressor, diaphragm or pressurised gas containeror reservoir.

What is claimed is:
 1. Toilet apparatus comprising a toilet pan, anoutlet pipe adapted to receive contents of the pan, a closeable lid onthe pan forming with the pan a waste receptacle chamber, a seal betweenthe lid and the pan, means for introducing water into the chamber towash an internal surface of the pan, means for increasing air pressurein the chamber to force the contents of the pan through the outlet pipe,a water trap seal disposed in the outlet pipe, and means for supplyingwater to replenish the water in the water trap after the contents of thepan have been expelled and compressed air is no longer being supplied tothe chamber.
 2. Apparatus as claimed in claim 1, wherein the means forincreasing the air pressure in the chamber comprises an air displacementunit.
 3. Apparatus as claimed in claim 2, wherein the air displacementunit comprises a piston in a cylinder.
 4. Apparatus as claimed in claim3, wherein the piston is actuable electromagnetically.
 5. Apparatus asclaimed in claim 3, wherein the air displacement unit has an outlet atone end of the cylinder connected to the chamber whereby movement of thepiston towards that end of the cylinder increases the air pressure inthe chamber.
 6. Apparatus as claimed in claim 5, wherein the airdisplacement unit has a second outlet at a second end of the cylinder,the second outlet also being connected with the chamber.
 7. Apparatus asclaimed in claim 3, wherein the piston in one stroke displaces a volumeof air sufficient to expel the contents of the pan.
 8. Apparatus asclaimed in claim 2, wherein the means for introducing water into thechamber includes the air displacement unit.
 9. Apparatus as claimed inclaim 8, further comprising a cistern for holding flushing water. 10.Apparatus as claimed in claim 9, wherein the air displacement unitcomprises a piston in a cylinder, and an outlet at an end of thecylinder whereby movement of the piston towards the end pressurizes thecistern and forces water from the cistern to the pan.
 11. Apparatus asclaimed in claim 9, wherein the cistern includes a siphon for deliveringwater to the pan to wash the internal surface of the pan.
 12. Apparatusas claimed in claim 11, wherein operation of the air displacement unitforces water through the/siphon to the pan.
 13. Apparatus as claimed inclaim 9, further comprising a float valve in the cistern, the floatvalve being responsive to a level of water in the cistern to release apressure in the cistern at a predetermined water level.
 14. Apparatus asclaimed in claim 11, wherein the siphon continues to deliver water tothe pan after a pressure in the cistern has been released.
 15. Apparatusas claimed in claim 1, wherein the lid is provided with a lockingmechanism for securing the lid in a closed position.
 16. Apparatus asclaimed in claim 15, wherein the means for supplying air includes an airdisplacement unit, and wherein the locking mechanism includes a lockingsensor to detect locking of the lid and initiate operation of the airdisplacement unit.
 17. Apparatus as claimed in claim 16, wherein the airdisplacement unit includes a piston in a cylinder, and the sensorinitiates movement of the piston.
 18. Apparatus as claimed in claim 17,further comprising a piston sensor provided at an end of the cylinder todetect the piston at that end and initiate movement of the pistontowards an other end.
 19. Apparatus as claimed in claim 1, wherein thelid and the seal are a removable unit.
 20. Apparatus as claimed in claim1, further comprising means for supplying to the chamber a volume ofwater sufficient to flush the contents of the pan through the outletpipe without increasing pressure in the chamber.